The Knights only play two top-eight sides on the run home but to finish with a 12-12 record, usually the minimum required to play finals, they now must win seven of their last eight matches.

To make matters worse, Newcastle prop David Klemmer is facing suspension after must he was sent off following the fulltime siren for making reckless contact to Daniel Saluka-Fifita's head in a tackle.

Newcastle might have been daring to dream of September football when they scored three of the first four tries, thanks largely to the efforts of Edrick Lee and Dom Young: the wingers who thwarted Gold Coast last weekend.

But once in position, the Rabbitohs became the latest team to expose the weaknesses in the Knights' goal-line defence, and did so without some of their most important players.

Campbell Graham, Hame Sele, Mark Nicholls and Liam Knight all suffered injuries in round 16, while State of Origin stars Cameron Murray, Damien Cook and Jai Arrow were also unavailable.

Things only became worse as the week wore on; winger Alex Johnston succumbed to a quad injury on game day and halfback Lachlan Ilias suffered a concussion just two tackles into the night.

But fill-in captain Mitchell took on more work in attack than in his first game back from injury last week.

Mitchell showed no signs of the hamstring injury that has stymied his season as he chalked up two try assists, two line break assists and a line break.

When Ilias was ruled out, bench utility Kodi Nikorima helped Walker shoulder the kicking load in the halves but it was Walker's boot that was the more destructive.

Walker forged a fruitful combination with Johnston's replacement Richie Kennar, who helped himself to a hat-trick just like his rival winger Young did last week.

"It was the best (win) I've been involved in in my time at the club, just in terms of character," said Souths coach Jason Demetriou.

"We had 40 per cent of our salary cap missing tonight and nearly 1200 games of NRL experience but no one blinked during the week.

"I have to give the senior players a massive wrap. I thought the performance tonight was outstanding."

Newcastle's first-choice hooker Jayden Brailey made his comeback from an Achilles tendon injury suffered in the pre-season but didn't get onto the field until the second half.

Less than 20 minutes into his long-awaited NRL return, the game appeared beyond Newcastle's reach and stayed that way.

Mitchell and Thomas Burgess will attract scrutiny from the match review committee after both were reported for high tackles in the first half.

Demetriou said it was "ridiculous" that Mitchell was put on report for a high tackle on Young while defending the line.

"It's a penalty, I get that, but he's made a bit of contact trying to wrap the ball up but it's not a reportable offence. No way," he said.

But Klemmer appears certain to face time on the sidelines. The prop forward's temper first flared up at Keaon Koloamatangi behind the play, but tensions boiled over in the dying seconds when he elbowed Suluka-Fifita's head in a tackle, sparking a melee.

He was sent off.

The Rabbitohs have dates with premiership heavyweights North Queensland, Penrith, Melbourne, Cronulla and Parramatta awaiting them but defeating Newcastle makes their finals equation a lot simpler.

Australian Associated Press